Substance Use and Addiction among Homelessness: A Scoping Review

Background Homelessness represents a multifaceted global challenge, closely linked to high rates of substance use disorders (SUDs). This intersection exacerbates health disparities and perpetuates social exclusion; however, effective, context-sensitive interventions remain limited. Objective This scoping review aims to synthesize present evidence on therapeutic, psychological, and social interventions for homeless individuals with SUDs, highlighting effective strategies and identifying gaps to inform future research and clinical practice. Methods Following the PRISMA Extension for Scoping Reviews guidelines, we systematically searched PubMed, Scopus, and ScienceDirect between January and June 2025. Inclusion criteria were peer-reviewed studies from the past decade, published in English, and investigating psychosocial or rehabilitative interventions targeting homeless individuals aged ≥14 with SUDs. Studies exclusively medical or without intervention components were excluded. A total of 23 studies were included. Results Integrated, multidisciplinary interventions—including Housing First combined with assertive community treatment, group-based motivational programs (e.g., AWARE, Tobacco-focused group motivational intervention), harm reduction approaches (e.g., Harm reduction treatment for alcohol, Extended-release naltrexone), and intensive case management—were most effective in reducing substance use, improving mental health and quality of life, and enhancing housing stability. However, the literature showed methodological variability, generally short follow-up periods, and limited incorporation of participants’ perspectives. Conclusion This review underscores the importance of flexible, tailored, and relationship-centered interventions to address the complex needs of homeless populations with SUDs. There is an urgent need for more rigorous and long-term studies, including qualitative insights, to better capture acceptability and feasibility. Strengthening synergies between housing, health, and psychosocial services—particularly in under-researched contexts, such as Italy— could foster more sustainable pathways toward recovery, dignity, and social reintegration.